In enterprise activities, utilization of a large amount of generated business data is indispensable. Therefore, a system that analyzes a database (hereinafter, “DB”) that stores a large amount of business data has already been devised.
In this analysis processing, a database management system (hereinafter, “DBMS”) receives a query and issues a data read request to a storage device that stores a DB.
As a technique of reducing latency for a data read in a processing for one query, a technique disclosed in PTL 1 is known. According to PTL 1, a DBMS generates a plan (hereinafter, “query execution plan”) which is a combination of a plurality of database operations (called DB operations or processing steps) necessary for executing a query, dynamically generates tasks for executing the processing steps, and concurrently executes the tasks to multiplex a data read request. For implementation of the task, according to PTL 1, any execution environment such as a process or thread managed by an OS or a pseudo process or pseudo thread implemented by an application or middleware can be used.